In Japanese Patent Laid-open No. 2004-32674 (patent document 1), an example of a front end module is disclosed which accommodates two communication systems, Time Division Multiple Access (hereinafter referred to as TDMA) and Code Division Multiple Access (hereinafter referred to as CDMA). In the example, a diplexer connected to an antenna, and a radio frequency switch and a duplexer connected to the diplexer are integrated on one multilayer substrate for integration. The signal of the TDMA system and the signal of the CDMA system are separated by the diplexer, the transmission and received signals of the TDMA system are separated by the radio frequency switch, and the transmission and received signals of the CDMA system are separated by the duplexer.
In Japanese Patent Laid-open No. 2003-249868 (patent document 2), an example of a front end module is disclosed which is designed to accommodate two communication systems, Global System for Mobile communications (GSM) and Digital Communication System (DCS). In the example, a diplexer connected to an antenna, a low pass filter (LPF) of the GSM side connected to one terminal of the diplexer, an LPF of the DCS side connected to another terminal are respectively formed as chip parts stacked in a multi-layer ceramic substrate. The three chip parts, a radio frequency switch connected to the LPF of the GSM side, and a radio frequency switch connected to the LPF of the DCS side are mounted on a resin multilayer substrate.